Thanks, but I do not understand what you mean by ‘composers’.
I read the Positional Alternates tutorial. Am I right in thinking that all features .init, .medi, .fina and .isol must all have the same number of glyphs for them to work? Because mine do not, ie. only lower case i, r and s need longer lead-in strokes (.init), but there are many more .fina glyphs.
I have the latest Adobe applications.
Paragraph panel > Options > select composer (single-line, world-ready)
I managed to make it work apart from one thing shown in pink.
But the OpenType properties are not available with the O icon is still the same, just available in the Character>OpenType pull down menu.
Only the classic Adobe composer offers that IIRC. Perhaps you have world ready composer on?
The features? No. If you replace one class with another, the classes have to be compatible (same number and order of glyphs). But you can have different classes in different features.
Adobe Paragraph Composer.
They’re a “single line”/“paragraph” version of the “Default” and the World Ready Composer (four options in total). The line/paragraph part doesn’t matter here.